In the last few issues, we took a look at several of the “Hard Parts For Your Fuelie” (Holley’s hot new EFI system). Previously, we touched on Holley’s modular Hi-Ram intake and followed up with an article on Holley’s new billet throttle bodies. One critical part of the EFI hardware puzzle that many forget or gloss over is the actual wiring harnesses. And in a fuel-injected application, the harnesses are considerable and sophisticated.

In the case of the Holley system, the harnesses were engineered from the beginning to be easy to install. While at first glance, the harness assemblies appear daunting, they’re actually clearly marked and in truth they’re essentially “plug and play” systems. By “clearly marked”, we mean that each of the connectors is labeled, basically telling you what they plug into. Depending upon the harness part number, there are several wires that are most likely not terminated. For example, on the main harness one non-terminated wire is the switched ignition power source wire (power when the engine is cranking). Others are listed in the ECU manual.

In the case of the 558-103 harness (LS2 Main Harness for Dominator & HP EFI systems) shown in the accompanying photos, direct-fit connections for stock style sensors include the following:

Manifold Air Pressure

Throttle Position Switch

Coolant Temperature Sensor

Crank Sensor

Cam Sensor

Stock Ignition Harness (Even/Odd)

Idle Air Control

Manifold Air Temperature

The harness also includes direct fit connectors for optional fuel pressure sensors, oil pressure sensors, and a wideband oxygen sensor.

Next up is the power harness. This is a simple harness with a non-terminated power lead and a ground lead. These go directly to the battery terminals. The main power ignition harnesses are designed for use with in concert with Holley EFI systems and they’re also plug and play arrangements. Like the main harness, the power harness is clearly marked.

Another harness you’ll need is for the wiring coils. Holley’s Number 558-309 kit is shown in the accompanying photos. This harness is used for Holley’s waste fire DIS coil package (four coils for eight cylinders). Like the other harness assemblies, they’re a straight plug and play arrangement. Here’s Holley’s info on wiring the coils:

Finally, the last plug and play harness is the Injector Harness. We’re showing Holley’s part number 558-201 in the photos. This harness connects the main harness to the fuel injectors (EV6 Style). You simply route the wires over the fuel rails, and plug the respective connector into the matching injector. Each of the wires is clearly marked, too, so it’s actually rather difficult to make a mistake!

We should also point out that Holley makes use of high-end OEM style connectors throughout. The harness assemblies are all nicely loomed and wrapped inside braided nylon style covers. Even for those who are “wiring challenged”, this is an easy system to hook up and it’s equally easy to route cleanly. For a closer look, check out the accompanying photos:

Here’s a look at the sample harness assemblies we examined in the text. From left to right: Injector Harness, Coil Harness, Power Harness, and Main Harness.

Bundle of snakes? Hardly. Look closely and you’ll see that the connectors are all clearly marked and for the most part terminated with OEM style connectors. One small loom mandates owner-termination (for installation in your particular car), but the ECU manual lays out what goes where.

This is the harness that is used to power the system. It wires directly to the battery (you’ll have to make the connection on the battery terminals). The balance plugs into the main harness.

This particular harness is for Holley’s fire DIS coil package (four coils for eight cylinders). Like the other harnesses, it’s a direct plug and play. The text provides more info.

The final harness is the injector harness. Again, this is another very simple to use, plug and play arrangement. Everything is pre-terminated and fitted with OE style connectors.

Both points/breaker-type and electronic ignition systems have their pros and cons, something I discussed in a previous article. As long as you’ve got a solid base to start from, with the right control module, an electronic ignition gives you greater control over your engine. Converting an older points/breaker-type ignition system can be pretty quick and easy or quite a bit more complex and involved, depending on what kind of system you decide to install.

There are two ways you can go about converting from points to electronic ignition – you can install a factory electronic system that replaces the factory points and distributor, or you can install an aftermarket high-performance system with parts and components from various manufacturers. With just a few tools, the factory system is ready to drive in just a couple hours. High performance street/strip/drag aftermarket systems are available from a number of different companies.

A conversion to electronic ignition can be as simple as removing the old points and installing a new magnetic pickup in the distributor.

Your Electronic Ignition Conversion/Upgrade Kit

Your car’s ignition system consists of two main components – the distributor and the ignition coil. The distributor is what controls where the spark goes and when it gets there, while the ignition coil supplies the spark. I installed a Mopar Direct Connect performance electronic ignition system in the old Charger I had because everything I needed – distributor, ballast resistor, and control module, were included and it was (and still is) the easiest to install and cheapest kit on the market. It was also the easiest to find. Since then, a number of other manufacturers have designed similar kits.

With a little research, you can also put together your own electronic ignition “conversion kit” from parts and components that are readily available. MSD and Accel are the most well-known names in this arena. Putting an ignition system together from aftermarket components usually means buying the control and distributor separately. You can also upgrade the fuel delivery system at the same time with the right control module.

Most Electronic Ignition System Conversions Begin with Changing the Distributor

An example of an electronic ignition distributor. You can tell it’s an electronic ignition model because there are two connectors on the side of the distributor.

There are electronic ignition conversion kits that make you remove the points and condenser and install a reluctor and pickup in their place. This will save you a few bucks and maintain the “OEM stock” appearance for the most part. However, kits that deliver the best performance require the replacement of the distributor which takes just a few steps.

Remove the distributor cap. This can mean popping a spring clip or turning a screw clip.

Note the location of the wire going to number one cylinder and the vacuum advance bulb.

Loosen and remove the distributor clamp/retainer bolt. Usually ½ or 9/16 inch, this bolt can be difficult without a special distributor/timing wrench. Loosen and remove the bolt with the distributor clamp and set them aside.

Remove the old distributor by pulling straight up. Wiggling and twisting may be required to help loosen it.

Install the new electronic ignition distributor. Align the vacuum advance bulb and rotor to that previously noted and push and wiggle the distributor into the block until fully seated.

Install the hold down and bolt. Thread the distributor clamp bolt with hold down and tighten to where there is resistance when moving the distributor left and right.

Install the new cap and wires. You’re installing a performance ignition system, which needs new wires. This can mean cutting the wires to size and installing connectors.

Installing a Factory Replacement Ignition Control Module

The OEM style Ford control module with blue wiring plug.

The hardest part of converting to electronic ignition using a factory kit is finding a location for the control module. My Mopar kit was four wires, power for the module and power and ground from the reluctor and pickup in the distributor. However, there was also a ballast resistor that I had to install before the ignition coil. The easiest way to mount the controller is to use self-tapping screws and a drill with a screwdriver tip. Mounting the ballast resistor is usually just a matter of removing the old stock resistor and putting the new one in its place. You may need to drill a pilot hole for it.

With the factory kit, installing the module consists of plugging the molded connector into the corresponding connector coming from the distributor and applying power and ground. With a factory kit this just means splicing the corresponding wires together. Installing an aftermarket kit may mean using a meter or test light to find the wires coming from the ignition key (brown and yellow on all 60s models Chrysler products).

An early Ford factory electronic ignition system with the components laid out for viewing.

Installing a Performance Aftermarket Electronic Ignition Kit

Aftermarket performance electronic ignition kits take more time and effort to install, although this isn’t to say that the installation is difficult. The hardest part of the job, again, is going to be finding somewhere to mount the control module and finding the “hot” wire from the ignition key. When deciding on a location for the box, you need to keep in mind what kind it is. For example, the Digital 6AL box from MSD has rev limiter switches on the top that you may want access to while driving thus, you’ve got to a find a spot that’s within arm’s reach. I’m going to use MSD’s Digital 6A/6AL as an example. You may have to look for different color wires.

Locate the heavy black and red wires from the control module and route them to the battery. Don’t hook them up yet.

Locate the orange wire and the smaller black wire in the control module harness and route them to the ignition coil. Black goes to coil negative and orange goes to coil positive.

Route the smaller red wire to where you can tap into the “Ignition” lead coming from the ignition key.

Route the violet and green wires to the distributor and connect it to the trigger lead from the distributor.

Route the grey wire to your tachometer and connect it to the tach trigger-usually a green wire.

Make solid connections to battery positive and negative with the heavy black and red wires.

Don’t forget the plug wires! Old and worn plug wires can oppose the flow of current and adversely affect performance and mileage.

Remember, you need to make sure that you mount the controller solidly to minimize vibrations. Many of them actually come with rubber isolators to protect them from vibration. Use them. Also, if you have to penetrate the bulkhead/firewall with any wires, make sure you protect the wires by installing a rubber or plastic grommet first.

Dress your plug wires when you’re done. Put them into looms or brackets to keep them away from each other (to diminish interference) and away from hot stuff like the headers.

What to Do If the Wires Are too Short

The wiring harnesses that come with electronic ignition control modules are usually pretty long and will reach where they need to go. Usually. Sometimes, though, you need just a little more length to get the wire where it needs to go. As long as you either solder (and seal) the connection or use quality solder-less/crimp connectors, you’re fine. Also remember to bump up the size of the wire you use by one. For example, if you have to add a few feet to the heavy black and red power leads, be sure to use at least 12 gauge wire. If you need to extend any of the other wires, be sure to use at least 16 gauge. These wire sizes are precisely calculated at the factory to deliver the required amount of current without overheating. Any added length adds to the wire’s resistance, thus we want to use a slightly larger wire when making extensions.

A Word about Ground Wires

I can’t remember how many times I’ve gotten a call to go help a friend or customer who installed their own aftermarket electronic ignition system and had problems that were related to ground. The main power lead should go directly to the battery and use a high quality eye connector. If you’ve got smaller grounds to connect, they should go directly to the frame or chassis and you should use a wire brush or sandpaper to remove corrosion, paint, rust, and anything else that will inhibit the flow of current.

Properly routed wires not only look better, they work better since they don’t cause interference or get hung up on the headers.

Timing It When You’re Done

Now that you’ve got everything (hopefully) installed correctly, it’s time to fine tune the installation by setting the timing. This is why you didn’t torque down on the distributor hold-down bolt when you replaced the distributor. Crank the engine up and disconnect and plug the vacuum advance line. Get the engine RPM into the ballpark (around 700-800 RPM) with the idle adjuster screw on the carb or throttle body.

Now, slowly and incrementally turn the distributor clockwise or counterclockwise, listening to the engine as you go. As you advance the timing into and just past ideal, the RPM will increase. When you’ve gone too far, the RPM will start to drop and the engine will start to stumble. Get the RPM into what sounds like an ideal speed range and tighten the hold down bolt. If you’ve got one, you can hoop up a timing light to the number one plug and the battery and set the timing to factory spec. However, I recommend doing a little “timing by ear” once you get the timing into spec to get the best performance possible.

In the last segment of Hard Parts For Your Fuelie, we took a detailed look at Holley’s modular Hi-Ram intake. If you recall, the Hi-Ram is essentially a modern high tech tunnel ram arrangement that can accept carburetors or throttle bottle injectors. There’s a special top available that allows you to use a lower profile air intake with a front mount throttle body. Holley offers several different throttle bodies for this application – 90-mm, 35-mm, or 105-mm models. The 105-mm job is available with either a straight bore or a tapered bore (we’ll get to the differences down the pate). FYI, the various throttle body mandate a specific manifold top.

For our purposes, we’ll zoom into the 105-mm jobs (with photos), but the 90-mm and 95-mm models are much the same. The smaller billet Holly throttle bodies are all built with what Holley calls a “Low RPM Taper”. That means that there is a tapered transition machined into the body that eliminates low speed (low RPM) drivability issues. Essentially, tapered models offer more pedal to throttle travel at low engine speeds to improve drivability on street and similar applications. As pointed out above, the 105-mm throttle bodies are available with a taper or with a straight bore. Throttle bodies without tapers are maximized for “RACE ONLY” applications. The actual throttle bores in all of Holley’s throttle bodies are larger compared to those found on competitor’s throttle bodies, too.

Holley uses a unique TPS “clocker” that allows the TPS to be rotated back into the ECU’s required idle voltage range. As a result, modified engines no longer suffer from problems related to TPS voltage. A PCV passage valve is included in the throttle body. This means that in forced induction applications, there’s no need to physically block the PCV port. Additionally, the PCV port can be rotated if there is a need for a different (than stock) orientation.

Holley also fits the throttle body with a bleed screw. Now, assuming that an engine has a very long duration, high overlap camshaft (with low manifold vacuum), a situation may exist where it is difficult to tune a poor idle by way of the ECU. With Holley’s throttle bodies, the included idle bleed is an adjustable passage around the throttle blade to increase idle performance, if needed. The bleed screw allows idle adjustment without affecting blade position and TPS output voltages at idle.

The actual body is machined from billet aluminum. You’ll note that the throttle plate is “slabbed” (heavily profiled) to improve airflow. The body is black anodized too. This means that it is resistant to corrosion.

All of Holley’s premium throttle bodies are engineered to work with cable drives. All have a cruise control provision as well. In terms of applications, Holley points out that the throttle bodies fit the following intake manifolds: Stock LS2, Stock LS3, Stock LS7, Holley LS Mid-Rise, Holley Hi-Ram (85 and 105-mm tops), Fast™ LSX, Edelbrock Pro-Flo XT using 4 bolt TBs as well as most other 90 through 95-mm LS intakes using 4 bolt throttle bodies.

Finally, Holley offers a throttle cable bracket for the big 95-mm and 105-mm throttle bodies used on Hi-Ram and Mid-Rise intake manifolds. This bracket has an allowance for throttle pedal adjustment or the addition of a nitrous plate. It works with throttle cables from 1998-02 5.7L Camaro and Firebird (GM Part Number 12563339) or aftermarket versions patterned after the GM component. You can also fit a cruise control cable from the same applications (various GM part numbers).

For a closer look at the billet throttle body, check out the following photos:

Holley manufactures several different billet aluminum throttle bodies. This is their large 105-mm job with a special low RPM taper. This means it is very streetable. The text offers more information.

Looking at the throttle body head-on, you can see the large slapped throttle plate. It’s carefully contoured to ensure maximum flow.

Here’s a look at the backside of the throttle body. The basic configuration fits a wide range of intake systems, although in this particular case (105-mm), you’ll need a dedicated intake (top) to accept the large bore.

It might not look like much, but this bracket is important. It allows you to hook up the throttle body to a conventional production line GM cable. It also allows the installation of cruise control (cable) using factory parts.

This is the tool that eliminates the Spiral Loc pain. It’s made by a company called “Lock-In-Tool”.

The wrist pin links the connecting rod to the piston in your engine. That’s simple enough. But the job of the wrist pin is absolutely critical. Should the pin move laterally, then sudden (and utter) engine destruction is pretty much guaranteed. It’s that simple. Now, there are a number of ways to keep a wrist pin locked within the piston. The most common is some sort of pressed pin arrangement or a floating pin with a lock ring of some sort. There are components out there called pin “buttons”, but for the most part, buttons are only used on supercharged drag race applications (blown alcohol, top fuel, etc.).

Pins that are pressed are likely the most common in passenger car applications. In this situation, the wrist pin is press fit into the small end of the connecting rod. The reciprocating motion necessary in the connecting rod-piston component of the engine occurs between the wrist pin and the wrist pin bore inside the piston. Engines designed with press-fit pins must have the rods and pistons assembled by an engine (or machine) shop using specialized equipment. Essentially, the small end of the connecting rod is heated and the piston is set in place over the rod small end. Next, the pin is pressed into place (through the pin bore in the piston, into the connecting rod small end).

In order to use the Lock-In-Tool, place this clip (which is supplied with tool) into lock groove of piston. It stops the wrist pin from sliding completely through the piston. Next, lubricate the pin with conventional 30 wt. oil and install it so that it seats against the clip. In this example, the piston was configured in a manner that really didn’t require the use of the clip. Here, both locks on the “open side” could be installed on one side without the wrist pin in place.

Wrist pins that “float” are regularly found in high performance engines. In this configuration, the pin physically floats within the connecting rod small end. Instead of being pressed in place, the wrist pin is held in place by way of one of three different types of locking devices – Spiral Locs, Round Wire Locks or Snap Rings (most often referred to as “Tru Arcs”). High performance pistons are machined with special wrist pin retainer grooves that accept the locking device (many are machined for double retainers per side). The most effective retainer, and perhaps the most common is likely the Spiral Loc (this is manufactured from a flat coil of hardened steel). Unfortunately, the Spiral Loc is also the most difficult of the wrist pin retainers to install. The photo below gives you a little more advice for installation.

Spread the Spiral Loc apart using your fingers and spin it onto the Lock-In-Tool. You have to spin the lock until the end of it reaches the registration mark on the end of the tool. The “registration mark” is a notch on the tool where the end of the Spiral Loc is positioned

Your car’s ignition system is responsible for converting the 12 VDC of your car’s electrical system to a much higher voltage and delivering that higher voltage as a spark at the proper time to each of the car’s spark plugs. This is a GM/Pontiac engine with GM’s high energy ignition (HEI) electronic ignition system installed.

There are currently two types of ignition systems in use in cars and trucks. The first is the electronic ignition system and the second is the distributorless ignition system (DIS). You can easily tell which you have when you pop the hood by looking at the spark plugs. If there are thick wires all running to the same location, you’ve got an electronic ignition system. Conversely, if you pop the hood and see a couple/three smaller wires running from a block on top of the spark plugs, or short thick wires running to what are known as coil packs, you’ve got a DIS system.

Prior to electronic ignition, which became ubiquitous in the late 70s and early 80s, there was also the points-type ignition system. This type of ignition system can be identified by the presence of a small aluminum can mounted either on the side of the distributor or very close to it on the engine. Quite often, except with newer electronic ignition systems, both points-type and electronic systems will also have what is called a ballast resistor mounted to the bulkhead behind and above the engine.

If you’re building up a strip burner basically from scratch, you’re going to need to decide what kind of ignition system you want to use. Unless we’re already building on a car that’s got a computer, our choices are going to be limited to standard electronic or points-type systems. I’m going to discuss the pros and cons of each to help you decide which one you want to go with.

An example of an electronic ignition distributor. You can tell it’s an electronic ignition model because there are two connectors on the side of the distributor.

What Tells Fire to Go to Your Spark Plugs

The ignition spark comes from the ignition coil into the center tower of the distributor cap. The spark travels through the cap and to the rotor underneath. The spark then travels along the conductor on the rotor to the plug tower corresponding to the correct spark plug.

Your ignition system is the electronic/electrical system in your car that sends properly timed sparks to your spark plugs to ignite the air-fuel mixture in the combustion chamber. On most ignition systems, the charge that creates the spark is created and contained by an inductive ignition coil. However, some performance ignition systems use a capacitor to store this charge.

This image shows a cap and rotor that is in dire need of being changed. Pitting on the cap and rotor terminals can easily be seen.

Whether an ignition system uses a capacitor or an inductor, the circuit creating the charge is broken, causing an electrical field on the ignition primary side to collapse, sending the charge to the proper plug on the secondary side. Points-type and most electronic ignition systems use a cap and rotor to pass the secondary, high current-voltage spark to the plugs. DIS systems use a series of sensors and switches to open and close the primary ignition circuit and fire the secondary side.

Standard Points Type Ignition System

Close-up of a points-type distributor. You can barely see the rubber nub riding on the distributor shaft cam with the points closed. Counting the cam lobes, you can see this is from a six cylinder engine.

The points-type ignition system uses a set of contacts, known as points, and a capacitor (to filter AC noise), known as a condenser, to break the electrical circuit, creating the spark. The points are attached to a plate in the distributor. As the distributor shaft rotates, a cam riding on a bumper on the points rides up and breaks the points contact. For this reason these are also known as breaker-type ignitions.

This image shows an eight cylinder distributor with the points open. The coil has just fired or is firing.

Pros and Cons of Points-Type Ignition Systems

These ignition systems are capable of passing large amounts of current and electricity, which makes them great for high performance automotive ignition systems. They’re also extremely accurate, also making them great race cars. I had an old Mopar (a Charger) that I first used on an Accel dual-point (the distributor held two sets of points instead of one) distributor in it. My big Holley 1100 double-pumper almost couldn’t pump too much fuel to burn. They’re also really easy to troubleshoot. No spark at the plug? Got power to the ballast resistor/coil? Pull the cap and make sure the points are opening and closing properly and are properly gapped.

Points and condenser plus condenser mounting strap.

The problem is keeping even single-point distributors properly adjusted. Performance engines vibrate, causing the adjuster to move over time. You’ll be adjusting the points between each pass on your strip burner to get the best performance on each run, I guarantee it. Also, even when you use the recommended lube on the cam and rider pad, both wear over time, especially the pad, as do the springs and plates inside the distributor, making them even harder to keep properly adjusted for maximum performance.

Close-up of a set of points.

However, when converting from a stock points system, they’re the easiest to do. Typically it’s just a matter of sticking in the new distributor, hooking up the power, installing a new coil and wiring it, and putting on new plug wires, and then timing it. It can be done in a couple of hours in your garage with minimal tools.

Electronic Ignition Systems

A close-up look at the inside of an electronic ignition distributor. As the reluctor passes the pickup, the primary ignition circuit opens, firing the coil.

Electronic ignition systems use a magnetic field to open and close the ignition primary circuit. Instead of an ignition breaker, a special type of transistor (which is called the pickup) that works with a magnetism is used. Instead of a cam spinning on the distributor shaft, a component known as a reluctor rotates with the shaft. This reluctor has several small magnets on it which pass the pickup as the shaft rotates.

The reluctor and pickup from an electronic ignition system. Sometimes you get lucky and this is all you need to change to convert to electronic ignition, along with adding a control module.

The primary circuit is opened when the reluctor magnet passes the pickup, sending a signal to the electronic ignition control module. The control module reads engine speed and throttle position to determine the timing and temperature for the spark. The ignition control module then opens and closes the primary circuit on the ignition coil, sending the spark to the distributor cap, through the ignition rotor, back through the cap, and finally to the plug.

Pros and Cons of Electronic Ignition Systems

This is an aftermarket performance electronic ignition system from MSD. Installation/conversion of this is much more involved than a factory system.

If you’re converting a car that wasn’t factory-equipped with an electronic ignition, the cons start with the difficulty of the conversion process, unless you install a factory electronic system (See image above the Direct Connection Mopar Performance ignition system I used). This is what I did with my Charger. Out with the old distributor, in with the new, mount the new racing coil I bought, and hook up a few wires and connectors. The hardest part was finding a spot for the control module and the over-sized racing coil that I liked.

Take a look at the MSD performance electronic ignition system in the image above. Not only will you need to replace the distributor and find a coil mounting location you like (although this coil actually fits in the factory location and mount), but you’re going to have to route the wires for the control module through the bulkhead between engine and passenger compartments. On top of that, you’ll have to find a place that you can securely mount the ignition control module. Taking that one step further, if you get one that allows you to make adjustments on the fly, you’ll have to find a place to securely mount in and that you can safely reach to make those adjustments.

If you’re not looking for all out racing power, this performance electronic ignition conversion kit from Mopar Direct Connect is ideal. It’s also quick and easy to install.

More things can go wrong with an electronic ignition system, too. The plate that the pickup is mounted to can wear and move, causing the reluctor and pickup to move out of adjustment and stop working. The reluctor itself can wear and chip in extreme cases. Competition systems have chips that control the function of the controller that can fail or wiggle loose and are not easy to diagnose right away. Don’t get the controller properly grounded and you can experience an intermittent ignition failure that is as hard to track as the Abominable Snowman.

An OEM ignition coil (left) and a performance aftermarket coil from Accel – an Accel SuperCoil.

The aforementioned ability to make ignition system adjustments while driving is one of the major selling points for high-end high-performance competition ignition systems. Most performance controllers are also equipped with rev limiters that can save both you and your motor in a runaway condition at the track. Keeping the spark timing (and heat) properly adjusted is much easier with electronic ignition systems. No moving parts that rub together and electronics that learn over time make this possible.

A performance standard points/breaker-type ignition upgrade consists of these items: New coil, distributor with cap and rotor, and new wires.

Electronic ignitions also allow for ignition coils that deliver more spark, such as capacitive discharge (CD) systems. Since they’re mostly solid-state, there is less to wear out. They’re also not as susceptible to timing problems when things in the engine compartment get wet.

Installation time varies depending on a few factors. The longest and most difficult install is going to be the conversion from an old points-type ignition system to an aftermarket competition electronic ignition system. Install time can take anywhere from a few hours to a couple of afternoons, depending on how familiar you are with tools and how much you know about automotive electrical systems.

Distributor-less Ignition Systems

This is a coil pack for a six cylinder engine with DIS, distributorless ignition system.

These are the new kids on the block. They’ve only been in regular use since about the year 2000, although they aren’t the only electronic ignition systems in use at the moment. They are the most involved ignition systems, although as the name implies, we’ve done away with the distributor. Now we use sensors to trigger the opening and closing of the primary ignition circuit.

Instead of a distributor with a cap and rotor direction the fire to the individual plugs, DIS ignition systems use a coil pack. A car can either have a single coil pack for multiple packs. Each coil pack contains at least one ground wire and multiple “hot” wires, all of which lead to the ignition control module, which have now become engine control computers that accept a wide variety of sensor inputs. Either or both a cam and/or a crankshaft sensor are used to tell the computer where the engine is in the rotation and what cylinder to fire.

Some DIS systems put the coil on top of each individual spark plug like this. These are called coil caps.

Pros and Cons of Distributor-less Ignition Systems

Because DIS systems use a larger number of input parameters to control spark duration, timing, and temperature, they are much more accurate, especially at higher engine speeds. This is extremely cool if your strip burner is also your daily driver and/or you’re operating on a tight budget. No need to dive in with tools and meters to adjust this and that. The computer takes care of everything. Even better, if you’ve upgraded your computer, you can plug your laptop in and make adjustments to everything on the fly. You can also swap out system “maps” between passes at the push of a button and click of a mouse.

If you’re working on an older car that was factory equipped with a points type ignition, forget converting to a DIS system unless you’re installing a special crate motor of you’ve got the tools, time, and experience to assemble a DIS motor. Cam and crank timing are minute with points and older electronic ignition systems, but they become microscopic when computers and DIS systems come into play. In most cases, every bit of wiring is going to need to be replaced.

Again, the level of control that a computer-controlled ignition system puts at your fingertip is amazing. Removing the wear item that a distributor is just makes your ignition that much more adjustable and adaptable. Over time, as wear gradually occurs, the computer can make small adjustments to keep performance at its peek.

Conversely, quite a bit more can go wrong, too. With points and older electronic systems, if ignition timing goes out of adjustment, fixing it is quick and really easy. DIS systems make you hook up meters and testers. Finding out why no spark is getting to the plugs involves quite a bit more testing and checking – wiring, coil packs, connections, sensors – some of which can be located behind the engine, and more. A no start condition can take you hours to find, but be nothing more than a connector with a wire loose because we’re talking about such small voltages and currents.

What I’d Choose to Install in My Next Strip Burner

What kind of ignition system I’d install in my next strip burner would depend on what year and make it is, the condition of the existing wiring, and if I’m building up a Nostalgia Drags car or something more of an Unlimited Drags car. If I’m going Nostalgia and electronic was available from the factory, then points it is.

However, if I’m going overall “ease of use”, which means both during install and on race day, I’m going with a high-performance aftermarket system like the MSD system pictured above. They’re not as hard to install as they look, they look cool, and they work really well. There’s also the fact that I’m not going to build anything that first hit the streets after the year 1980, and there’s no way I’m plunking down all the dinero that going high-performance DIS would require.

Many of you may remember the days when power brakes weren’t even an option, let alone a standard feature. Brake boosters use one of two different methods to enhance the amount of braking pressure exerted by your foot on the pedal. However, technically speaking, systems using only one of these methods are correctly known as “power brakes.” The other method used is properly called “power-assisted brakes.” Here, we’ll review the two types of systems and how they work, looking a little at some diagnostic and troubleshooting methods for the type of power brakes used in the vast majority of passenger cars and light trucks.

The Difference between Power Assist and Power Brakes

There aren’t many people out there that really know this difference. To them, any system that multiplies the power you input the brake pedal to slow and stop the car is a power braking system. In the simplest of terms they are correct. However, we use the two different terms to tell the difference between the two types of assist systems-hydraulic pressure and vacuum.

Systems using hydraulic pressure to assist driver braking input are no longer used on new production passenger vehicles although they are still used on some larger commercial vehicles. These systems have a booster mounted to the bulkhead in front of the driver. Attached to this booster is a pressure line attached to the power steering pump. When the driver steps on the brake, fluid is allowed to enter the booster behind a diaphragm. The fluid pressure presses against the diaphragm and multiples the driver’s braking input. This system is also known as a hydratech braking system. Just to qualify what I said above: I’ve been involved with the automotive industry in the US for about 40 years now and have only personally seen this type of system installed on large commercial vehicles and much older passenger vehicles. This isn’t to say that there isn’t someone out there still using it.

The type of brake system that we have today is a true power brake system. There is the booster against the bulkhead. Attached to the booster is a vacuum line going to the intake manifold and supplying manifold vacuum (Manifold vacuum is highest when decelerating). Vacuum is constantly supplied to the master cylinder side of the diaphragm. When the driver steps on the brake pedal a valve behind the diaphragm opens. This applies atmospheric pressure to the diaphragm. This outside air pressure multiplies the driver’s brake input.

This is what an empty master cylinder should look like after 10-20 years of use when the system has been properly cared for.

Diagnosing Power Brake Booster Problems

Most problems with power brake boosters can be narrowed down to a single type of problem: leaks. Either the valve that lets in outside air pressure when the brakes are applied is leaking, the front seal on the booster is leaking, the vacuum line is leaking, or the diaphragm inside the booster is leaking. Another problem, although pretty rare is the valve that lets outside air pressure in doesn’t want to open when the brakes are applied.

All of these problems, except the leaking air pressure inlet valve will result in you having to apply more pressure to the pedal than normal. A leaking air pressure inlet valve will cause your car to feel like the brakes are dragging-because they are. You may even have people telling you that your brake lights are constantly on if the leak is big enough as it will draw the brake pedal down and activate the brake light switch on the pedal. That inlet valve is non-replaceable. The booster has to be swapped out.

Diagnosing the Cause of a Loss of Braking Power

You’re driving down the road and need to stop, quickly. You apply the brakes, but it almost feels as though nothing is happening, although the pedal feels normal. You press harder and the car begins to stop. If the brake pedal doesn’t sink to the floor, most likely you’ve got a vacuum leak that needs to be fixed. Pop the hood and look at the junction between the master cylinder and the booster. Wetness right here is an obvious sign that the booster’s front seal is leaking and that it has caused the master’s rear seal to leak. Both will need to be replaced, which I will describe below.

Ok, so how do you determine where the problem is if there is no wetness present? Grab a mechanic’s stethoscope or just a piece of tubing about ½ inch in diameter and about 18 inches or so long. Start the engine. Put the stethoscope on and slowly move the end of it around the master cylinder, booster, and vacuum line. Listen for a hissing sound. Turn off any other source of noise that you can to make the hissing easier to hear. If you’re using a piece of tubing, stick one end in your ear and slowly move the other end around the components. If you don’t hear any hissing, loosen to two nuts securing the master to the booster (5/8 inch wrench or socket required) a little. Still don’t hear any hissing? Have someone slowly and carefully depress the brake pedal. Ahh! There it is! Replace the booster to fix.

Manipulate the hose leading to the intake manifold with the engine running. If you see any cracks or tears, replace the hose. If you hear any hissing, localize it. Is it the hose or the fitting leading into the booster? Replace the problem part. The valve/fitting just pulls out with a little effort and pops back in with the same amount of effort. You may have to twist and turn the hose to get it off, especially if they’re old as heat will have begun to melt the rubber to the plastic.

If you can hear but not localize the hissing, carb cleaner will help you locate the leak. Carb cleaner has volatile hydrocarbons that your engine really likes in small quantities. Use the included hose to direct the stream around the various possible points of leakage with the engine running. Go fairly slowly as the chemicals have to get into the combustion chamber to make a difference. When you spray over the area that’s leaking, you’ll hear and feel the engine speed up a bit and then settle back down.

This is a really extreme case of a contaminated master cylinder. The sludge has gotten so thick it resembles axle grease in consistency. Although this is recoverable, I would normally replace the master cylinder and then flush and bleed the system.

No Leaks Located

You’ve gone through the steps above to diagnose that hard brake pedal but have found no leaks in the vacuum portions, so what now? Verify that the master cylinder has fluid and that the pedal doesn’t sink to the floor with moderate/normal braking pressure. This eliminates leaks in the fluid side, but doesn’t eliminate the fluid side as the culprit.

Pop the master cylinder open and look at the fluid. New brake fluid is clear, usually with a slight yellowish tinge to it. Old, contaminated fluid is dark brown. Using a flat blade screwdriver, lightly scrape along the inside bottom of the reservoir and pull the screwdriver out. It should come out clean, with just a few drops of fluid on it. (Don’t let those drops hit the paint!) However, if your car is an older one, chances are it will have a layer of sludge on the bottom of the blade. A little bit of sludge is to be expected. However, if most of the screwdriver blade is coated with it, you need to flush the system. Sludge can get into the small orifices throughout the system and crud the system up, causing it to lose efficiency, and, if not fixed, can lead to those orifices becoming completed clogged and a loss of brakes.

Flushing the system isn’t as hard as it sounds, it can just be a little time-consuming, especially if you have to do it alone. Before starting anything, grab the things you’ll need: a good-sized bottle of the correct DOT-rating brake fluid (Check your owner’s manual or the tag that may be inside your glovebox. Most pre-2000 cars use DOT 3 fluid.), a bottle of DENATURED alcohol (regular alcohol will eat the rubber components and cause leaks), and a 3/8 inch wrench. It’s also a good idea to get a couple of drain pans. Follow these steps:

Remove the old nasty fluid from the reservoir. I use an old turkey baster.

Refill the reservoir with the denatured alcohol.

Place the catch pans under the rear wheels (Yes, jacking the car up helps, but is not necessary.) where the wheel cylinder/calipers are.

Crack open the bleeder valves on the rears and allow them to drain.

Allow both sides to drain until they start to flow fairly clear. Keep the reservoir full of alcohol. Close the bleeders.

Make sure the reservoir is full.

Move the pans to the front wheels and repeat 1-6 above.

Unless you’ve got a one man bleeder kit, you’re going to need a helper now. Promise them a beer or two for their time. What we’re doing here is using a little of the braking pressure the system develops to help clean the system out. Refill the master with alcohol and go back to the rear. If you’ve got a one man bleeder, attach it to the bleeder screw on the right rear and loosen the screw a little. Pump the brake pedal three to five times. Close the bleeder and move to left rear, right front, and finally left front and repeat until each bleeder pushes out clean fluid. Suction out the alcohol and refill the master with brake fluid. Now it’s time to bleed the brakes.

This is what contaminated master cylinders and brake fluid typically look like after the old fluid has been suctioned out of the reservoirs.

Bleeding the Brakes

This is best done with two people if you don’t have an expensive pressure bleeder. You can use the one man bleeder, but it’s not easy to know when you’ve gotten any and all air bubbles out of the system. With the one man bleeder, make sure there is enough fluid in the bottle to cover the hose, attach the bleeder to the right rear (LR, RF, then LF). Loosen the bleeder and pump the pedal four to five times. Close the bleeder and move to the next wheel until all four are done.

If you’ve got a helper, when you move to anew wheel, attach the bleeder bottle to the bleeder valve and have your helper pump the pedal five times and hold it as though they’re sitting at a light. Pop the bleeder open and watch for bubbles. Your helper needs to inform you when the pedal hits the floor (but they shouldn’t be trying to force the pedal to the floor.) They are not to release the pedal until you close the bleeder valve and tell them to. Otherwise air will enter the system and defeat the purpose. Repeat this until all the air has been removed from the system and the fluid runs clear.

Replacing the Power Brake Booster

Replacing the power brake booster is a really straightforward process shouldn’t take any more than an hour. It’s only six bolts/nuts, two in the engine bay and four under the dash in the passenger compartment. Loosen and remove the two nuts securing the master cylinder to the brake booster. Carefully slide the master towards the front of the car until the studs are fully disengaged from the master. Don’t kink the brake lines.

Worm your way up under the dash. No, it won’t be at all comfortable. Loosen and remove the four nuts securing the brake booster to the bulkhead. Disconnect the booster input rod from the brake pedal. This could be a simple clip, cotter pin, or a nut and bolt, depending on year, make, and model of car you’ve got. Push the booster from the back to loosen it. From the engine compartment side, pull the booster out. Installing the new booster is a simple matter of reversing the above steps.

]]>http://www.racingjunk.com/news/2015/07/16/brake-boosters/feed/0In Tune With The Times – Figuring Timing Lights Part IIhttp://www.racingjunk.com/news/2015/07/09/in-tune-with-the-times-figuring-timing-lights-part-ii/
http://www.racingjunk.com/news/2015/07/09/in-tune-with-the-times-figuring-timing-lights-part-ii/#commentsThu, 09 Jul 2015 16:59:40 +0000http://www.racingjunk.com/news/?p=16389Last issue, we took a sort of look at timing lights. But what’s the big deal if your timing light is off a degree or two at 2,500 RPM? While it might sound like a marginal amount, keep in mind that whatever error exists in the light at low engine speed levels will be multiplied as the engine speed increases. If the light is off by two degrees at 2,500 RPM, it might be off by eight or ten degrees at 8,500 RPM – and, as you can imagine, that happens to be a significant amount of error.

To determine the accuracy of your particular timing light, it should be checked against a digital engine analyzer at speeds below 2,500 RPM. Be certain that your light is installed properly (see below) Unfortunately, you can’t trust all digital analysis equipment over the 2,500 RPM ceiling.

Autotronic Controls Corporation (makers of the MSD ignition systems) recognized this problem and began to test a rather large number of available timing lights. Through this testing, they decided to develop their own timing light. Additionally, this testing also revealed that an older model Sears Craftsman Timing Light (P/N A-2134 – still available used on that big auction site) was considered very reliable and accurate. Both lights are stable and accurate from zero to 8,000 RPM and because of this, they are well-suited to a modified (as in “drag race”) application. I’ve had the opportunity to test these lamps against several well known “professional” models, and I found that a few of the other lights were showing much different timing at engine speeds slightly over 1,200 RPM. At the same time, the MSD light and the Sears light were virtually identical in performance. And yes, these two lamps compared favorably with a digital engine analyzer below 2,500 RPM.

There’s more to timing lights, too. In truth, many enthusiasts (and believe it or not, that includes many of us in the drag racing community) hook up timing lights incorrectly. It sounds bizarre, but it isn’t. Often, a convoluted header configuration coupled with a tight engine compartment will only allow one easy light installation. Trouble is, that installation might not be correct. If the timing light is set up incorrectly, the timing marks you are watching could be a mile (and more than a few degrees) off. According to MSD, when setting up your timing light, there are several things to consider:

Be absolutely certain that the positive and negative clips are correctly attached to the battery or power source. Never use the coil as a source of power! Be certain that the pair of timing light power cables are not in contact or close to any of the spark plug wires.

When connecting the trigger clamp to the number one cylinder, be absolutely positive that the clamp does not come in contact with any other spark plug wires. If contact is made or if the trigger is close to any other wires, there is a good chance that a false triggering will occur. Additionally, it is always a good idea to further separate the number one cylinder wire lead from any other cylinder wires. Stray signals or spark crossover will not influence the timing light if this practice is always followed.

Some timing lights require the trigger clamp to be mounted in a specific direction on the spark plug wire. Be absolutely positive that your clamp is mounted with the jaws pointing in the proper direction. In the event that the clamp is installed upside down (and it’s very easy to do), the timing will appear retarded.

As you can easily see, there’s much more timing lights than simply hooking up the power cables and clamping the inductive pickup over the number one cylinder. Who knows, there’s a chance you could find some serious power lurking in your engine? And only because you were fooled by a faulty timing light.

As we pointed out in the first segment, this vintage Sears timing light has proven to be accurate and reliable.

Be positive that the inductive pickup clamp is correctly oriented. Virtually all timing light clamps have arrows or instructions which indicate the proper orientation. If the clamp is installed backward, then the engine timing will appear retarded.

Never allow the trigger clamp to come in contact with any of the other spark plug wires. If the trigger clamp or the wire that connects to the clamp are close to spark plug wires other than number one, they can influence the timing. Similarly, the power wires can pick up false signals if they run too close to the primary ignition wires.

Keep Reading to find out how to save time and money fixing brake problems yourself.

Imagine you’re driving down the road and the light changes. You step on the brakes and . . . you start slowing down and your foot slowly sinks to the floor. Then, nothing, you’ve got no brakes. But wait, when you check, the master cylinder is full! You could take your car to a shop and (sometimes) pay to have it inspected/diagnosed, but this can be a time-consuming process that often requires an appointment. What if I told you that finding and fixing most brake problems that originate under the hood is actually pretty simple and you can normally do it in less than an afternoon? Well, it is, and I can. Keep reading.

This is an example of a power master brake cylinder with cast metal body and power booster out of an early model Buick Riviera.

First let’s talk about what I mean when I say master cylinder and brake booster, as not all of us know yet. The master cylinder is the brake system component under the hood that sits against the firewall/bulkhead between the engine and passenger compartment fright in front of the steering wheel. On older cars, it’s metal and has a flat metal (cast steels) cover held on by a banjo that snaps over and into grooves on top of the cover. On newer cars this is an aluminum body with a plastic fluid reservoir and a cam-lock cap. The brake booster is mounted between the master cylinder and the wall on newer or converted/upgraded cars. See the images above and below.

This is an example of an aluminum-bodied master cylinder with a plastic reservoir.

The Brake Pedal That Slowly Sinks to the Floor

I first have to mention that I don’t mean that the pedal sinks to the floor when you apply your whole to it. I’m talking about the pedal sinks to the floor with nothing more than normal braking pressure applied. You know that a pedal that sinks to the floor is a sign of a leak in the system and a slowly sinking pedal means a slow leak. However, you’ve spent an hour or more under the car looking, you’ve even used a leak detector kit. What’s really got you scratching your head is the fact that the reservoir is full.

Blown up drawing of a master cylinder. A bypassing master cylinder leaks between pressure and return ports for one or both reservoirs.

What I’ve just described is a brake master cylinder that is bypassing. One or more of the inner seals on the piston inside have failed and fluid pressure is bypassing that/those seal(s) and returning to the reservoir. The fix for this is either replacing the master cylinder or rebuilding it. Neither is really difficult. Replacing is in and out with a slight detour, while rebuilding isn’t much different than rebuilding calipers once you’ve got it off and apart in that both require you to ensure the seal mating surfaces are blemish-free. I’ll describe the R&R process below.

The Brake Pedal That Feels Like a Weak Spring

This is the brake pedal that goes farther than normal and then feels like it wants to bounce back a little. Braking force applied to the wheels is lower and you have to step on the pedal harder to stop the car. This is air in the brake lines. Air is compressible, while fluid isn’t. This property of brake fluid is what makes it ideal for use in automotive brake systems, while air is pretty bad. The fix for this is to bleed the air out of the hydraulic system, bleeding the brakes. I describe bleeding the brakes at the end of this article.

The Brake Pedal That Stays Hard but Doesn’t Stop the Car

This is a photo of a non-power master cylinder from an early model Pontiac Grand Prix. Notice the bleeder kit at the bottom of the image.

Your car has power brakes but it feels like you have to stand on the brake pedal to get your car to stop, even at city street speeds. It’s worse than the days before power disc brakes if you’re old enough to remember them. The technical diagnosis for this condition is “gunk in the lines and orifices”. You see, brake fluid is hygroscopic, which means it absorbs water (even in a sealed system) which causes rust and sludge buildup. The combination of “gunk” can clog up the small orifices in the brake system as well as the small brake lines, reducing system efficiency.

You can verify this by scraping the tip across the bottom of the fluid reservoir and seeing if anything sticks to it. The fix for this is to suction the old fluid out of the master and flush the system, preferably with denatured alcohol and then fresh fluid. This process is described in Step 7. If you have drum brakes I would highly recommend cleaning out the wheel cylinders also, which I’ll describe in a later article. Also, use only denatured alcohol as anything else will deteriorate the rubber seals in the system.

You Hear a Hiss When You Step on the Brakes

There you are coming to a stop light or sign. You apply the brakes and as you’re coming to a stop, you hear a hiss that sounds like air escaping from a tire or balloon or the sound a snake makes. Chances are you’re also thinking to yourself that the pressure you’re applying is more than normal for power disc brakes.

What you’re describing is a power brake booster that is suffering a leaking seal, either inner or outer. A brake booster outer seal that’s leaking is likely to be accompanied by signs of wetness between the master cylinder and power booster because it will cause the piston seal on the master cylinder to fail due to being put under a vacuum. Your only repair option here is to replace the power booster. If you’re seeing signs of leakage from the master, you’ll also either have to rebuild or replace it.

Removing the Brake Power Booster and Master Cylinder

Retrofit master and booster for an early model Cadillac. The black thing on the side is a combination vacuum inlet and check valve. Braking power is boosted by using engine vacuum.

You’ve got to remove the master cylinder in order to get at the brake booster. If you only need to replace the booster, you don’t need to pop open the brake lines on the master, so all you’ll need is a wrench to remove the master (usually 5/8″ or 9/16″) and a socket (same size) and extension(s) and maybe a swivel universal. If you’re not taking the master out of the car to work on or replace, skip to step two below:

Loosen and remove the brake lines at the master cylinder. These are usually either 3/8″ or 7/16″. It is best if you use line wrenches, especially if the fittings look rusty as they’re designed to not round the corners of the fitting. A little WD-40 can make this easier.

Use a wrench to remove the two nuts that secure the master cylinder flange to the brake booster by turning them counter clockwise. WD-40 again.

Once you’ve got the nuts off, if you’re going to work on the master, remove it from the car and put it on your work bench or the ground for the moment. If not, simply move it forward enough to slide off the booster studs.

Inside the car and under the dash you will find either two or four (usually four) nuts or bolts securing the brake booster to the firewall/bulkhead. This is easier with the socket and swivel.

Disconnect the brake booster piston from the brake pedal. This might be a nut and bolt connection or a pin through an eyebolt secured with a cotter pin or locking pin.

Remove the booster from the car from the engine compartment.

Installing the New Brake Booster and Master

Installing the new power brake booster is just removing it in reverse, unless you’ve either worked on the master cylinder or replaced it.

Slide the booster piston through the large hole in the bulkhead. Align the bolt holes and push until the booster is flush to the bulkhead.

Install and tighten the nuts/bolts securing the booster to the bulkhead and connect the piston to the brake pedal.

If you’ve disconnected the master cylinder, you need to bleed it. New masters come with bleeder kits which are nothing more than rubber tubes attached to plastic fittings. If you’ve only rebuilt it, you can buy a bleeder kit for cheap at places like Autozone. I’ll describe this later.

Slide the master cylinder over the studs on the brake booster. Install and tighten the nuts.

If you’ve removed the brake lines, reinstall them and tighten them using a line wrench.

Bleed the brakes following the directions in Step 10 of the linked article.

Bleeding the Master Cylinder

After attaching the new or rebuilt master cylinder to the brake booster, thread the plastic fittings of the bleeder kit into the cylinder ports and route the hose(s) into the reservoir(s). BY HAND, slowly depress the brake pedal. have someone watch and let you know when no more air bubbles come out of the hoses. Remove the bleeder kit and reattach the brake lines to the master cylinder. Bleed the brake lines completely, rears first then fronts. If you have a vise mounted on a solid workbench and a large Philips screwdriver, you can mount the master on the vise to bleed it. This is easier.

]]>http://www.racingjunk.com/news/2015/07/07/finding-and-fixing-problems-with-master-cylinders-and-brake-boosters/feed/0In Tune With The Times: Figuring Timing Lightshttp://www.racingjunk.com/news/2015/07/02/in-tune-with-the-times-figuring-timing-lights/
http://www.racingjunk.com/news/2015/07/02/in-tune-with-the-times-figuring-timing-lights/#commentsThu, 02 Jul 2015 16:46:45 +0000http://www.racingjunk.com/news/?p=16374“Who cares about timing lights? I’ve timed the engine in my race car a thousand times. It runs right; It doesn’t sound like it’s detonating; What more do I need to know?” There’s no question that timing lights are anvil-basic devices and are easy to use, but contrary to what you might first think, all timing lights are not created equal. Before we get into lights, think about this: The idea behind setting initial timing is to synchronize the firing “point” of the ignition with the position of the piston in the cylinder bore. In order to establish this synchronization, you use a timing light to determine piston position relevant to a number of degrees marked on either the harmonic damper or the timing tab. The only real problem with setting up timing in this manner is the fact that your timing equipment must be absolutely accurate. Correctly indexed harmonic dampers, as well as properly indexed timing tabs, are crucial.

While it might come as a surprise to most serious racers, some (no, make that many) timing lights are not accurate! The reasons are varied, but in the majority of cases, timing lights have been designed for use in “more pedestrian, Mom and Pop” applications. Most tune-ups (professional and otherwise) seldom, if ever, require that the timing be checked beyond 2,000 RPM. As a consequence, many timing light manufacturers are able to construct a very simple, cost-effective timing light. And the key here is “cost-effective”. In some instances, a trigger delay is installed in the light (this practice is even found in some very high dollar “professional name brand” lights. I won’t name them. Just think mega buck). This has little impact in the lower engine speed ranges, but once the RPM level goes over the 2,000 RPM range, timing lights with delay circuits appear retarded. Another real problem is radio frequency noise protection. Most home-use timing lights have little if any protection against RF noise and as a result, can produce erroneous readings when used in conjunction with solid core wire sets.

According to MSD research, certain types of timing lights with built-in adjusting mechanisms (usually the common “dial back” models) have been proven to be so inaccurate that they produce false readings at speeds in excess of several hundred RPM. Many of these adjustable timing lights also carry very high price tags. Before you purchase such a unit, compare it to a known timing light.

That’s not the end of it, either. Next issue, we’ll look at ways to test your timing light. We’ll look at the right way to use your timing light, because, believe it or not, there are some misconceptions out there. Watch for it.

This is an old Sears timing light I regularly use. It’s reliable and accurate.

Both timing light power cables should be affixed to the battery. In the event that your race car has a trunk mount battery or pair of batteries, add a power junction block to an accessible location in the engine compartment. Never use the coil as a source of timing light power.

Number One ignition wire must be well separated from the other wires on the engine. Spark cross over from other wires can easily influence timing light performance.

These days, traditional h-pattern gearboxes are being replaced by paddle-shifters because of the inherent efficiency and fuel economy they offer. While it’s a shame, it’s an understandable move forward. However, it does separate the driver from his machine. Not only is shifting the old-fashioned clutch-and-stick assembly lots of fun, but it gives the driver a visceral connection with the car and it helps reveal the car’s behavior. While shifting seems simple, there are a few instances in which tricks like skipping gears and short-shifting will come in handy. Learning the intricacies of your transmission will save you money, shorten your lap times, and make you sound (and hopefully drive) like someone world-class.

Learning to shift gears all revolves around the idea of accessing the peak, or ideal, power and torque figures at any given moment. These figures occur within a range of revs known as the “power band” and outside of it the engine is either sluggish or inefficient. When we’re dawdling around town in our manual transmission-equipped car, we keep the revs low to save gas. But when we want to accelerate onto the freeway, we have to rev the engine higher as the peak power is typically made towards the top of the rev range.

Learning how to use this will take you far.

Maximizing the Engine’s Potential

When we’re on track and efficiency goes out the window, we begin looking at the transmission in a slightly different light. For instance, before we begin braking for an upcoming corner, we have to employ a technique known as “heel-and-toe” to ensure a smooth down-change which will lead to a responsive pickup when it comes time to accelerate out of the upcoming corner. Because we are braking and our engine revs are dropping, we have to focus our attention on selecting the right gear so that we are in the power band when exiting the corner. So, as we’re braking, we depress the clutch, select the appropriate gear, roll the heel of our right food (which is still exerting constant pressure on the brake pedal) onto the throttle to raise the revs by a thousand or so, and release the clutch to engage the gear. This may appear to be a daunting amount of multitasking, but it quickly becomes second nature.

One mistake to avoid when down-changing is shifting too soon. In order to avoid over-revving the engine, since engine revs will naturally increase when a lower gear is selected and the rolling speed remains the same, it is important to spend a good period of time braking and reducing both the road and engine speed before downshifting. This way, you allow the engine to rev up at the right time and avoid it spiking past the red line, which cannot be prevented by the rev-limiter in this instance.

Another problem with downshifting is not matching revs correctly. If the engine has to raise the revs without your heel’s assistance, it exerts a force known as engine braking, which is tough on the driveline and can lock the rear wheels if done too harshly. This is avoided by applying the correct amount of revs while down-changing. Just get that heel over the throttle and don’t worry about too much or too little – usually a small, audible “blip” in conjunction with a smooth release of the clutch is fine.

The complexities of downshifting can be summed up in one word: timing. Get the synchronization of inputs right and there’s little to worry about. On the other hand, up-shifting, while less technical, requires a certain amount of “feel” and improvisation.

Proper blipping requires a bit of dexterity.

Shifting Up

If you’ve heard the term “short-shifting,” you’ve heard someone making a reference to the act of shifting well before the end of the power band. This is because, on occasion, it allows for a smoother, faster exit from a corner. Shifting mid-corner is not desirable and can often result in a slide, a drop in revs, or both. In long corners where the driver is applying power gently and keeping steering lock on for a relatively long time, it sometimes helps to shift up prematurely so that when the throttle can be fully applied, the driver won’t have to lift and change gear. In effect, a bit of entry speed is sacrificed by shifting early so that the power can be applied safely and for a longer period of time. If the shift is done before the car is fully loaded up, it should allow for a smooth departure from the corner. This takes a certain amount of feel and familiarity with the breakaway characteristics of your car and your tires, but just remember that shifting is ideally performed when the car is as straight as possible.

Skipping Gears

For as long as I can remember, there has been a debate about whether or not to downshift sequentially or to skip gears. Shifting sequentially is more commonly used, as it’s easier to measure the amount of blipped-revs necessary, but it also exerts a stabilizing effect on the rear end. I’ve heard of it described as a rudder and can be especially helpful when driving on a wet surface. Skipping gears, on the other hand, will save the clutch some wear-and-tear if executed correctly. There are occasions where skipping gears becomes necessary, like when you lose a gear mid-race and must avoid it while changing down. However, it requires a deft pair of feet. When skipping, synchronizing the release of the clutch and the blipping of the throttle become more important as the change in relative road speeds is greater, and therefore the rev-matching needs to be done almost perfectly. As a rule of thumb, you will need to apply a prodigious blip when skipping gears, but it depends on how closely your gears are stacked together.

Loose Surfaces

When traction is low, it’s important to remember that sometimes, lots of power will not move you forward any faster. You’ll note how rally drivers will occasionally select a higher gear to limit the amount of available torque and therefore, wheelspin. Having slightly less response and power on hand can keep the care more composed and less skittish. Like with short-shifting on a dry track, staying on the power for longer will sometimes prove faster than being at the peak of the power band, but it all depends on the amount of grip available. Learning when to shift and how to control the output of your engine will give you a better understanding of your car and how to best utilize it. When you hear purists bemoaning the h-pattern going extinct, it’s for a good reason! As we’ve seen, learning how to properly shift an h-pattern gearbox will illustrate how minor inputs can effect the behavior of the car and instill a sense of mechanical sympathy. Though what purists moan about has nothing to do with efficiency or the prolonging of gears. It’s the sheer fun of rowing up and down, revving the engine on the down change, and the almost Riverdance-like footwork that goes on during a bit of heel-and-toe. It is the interaction between the car and the driver, which, while measured and explained with rationale, is an emotional process that is hard to let go of.